This invention relates to printed sound and, more particularly, to a system for generating audible information from indicia printed in ink on paper.
There have been various past attempts to produce a successful "talking book " which offer the reader, typically a child, audible guidance concerning the pictures and words he sees before him. The potential educational and amusement advantages of combined audio/visual presentation from a book are well documented. However, schemes for providing a commercially feasible talking book have largely failed due to the expense of providing an acceptable audio recording media in the book.
The two most prevelant schemes involve magnetic tape stripes or embossed plastic grooves secured to the book pages. These schemes are both economically deficient in that they involve the attachment of special materials to the individual book pages during manufacture. Publishing is normally highly mechanized, and any procedure which substantially lengthens the manufacturing cycle or adds significant labor, material, or tooling costs would render the books produced thereby non-competitive from a price standpoint.
It has been previously suggested that sound patterns could be applied in ink to a printed page by conventional printing means and then recovered by a reader using a hand-held optical pick-up means. For example in the U.S. Pat. No. 3,474,194, of Lees and Kinzie, there is disclosed a system of this type wherein variable-area ink patterns and applied to a page for later reading using a hand-held optical transducer.
The use of printed sound patterns alleviates the manufacturing problems referred to, but new problems relating to the mode of storage and the reading thereof immediately become apparent. The resolution capabilities of printing ink on standard quality paper are limited so the efficiency of this storage media from an information-content standpoint is a basic problem. The inability to obtain very finely distinguishable ink lines results in the usage of relatively large areas to record even a short segment of speech information. It would, for example, be desirable to provide a printed sound track directly underneath the printed text to which it applies, but the inordinate amount of space required using conventional sound track techniques renders this difficult at best since a large percentage of the page would then be needed for the sound track. To illustrate, the U.S. Pat. No. 2,369,572 of H. Kallman discloses a "dictionary" wherein each line of a page consists of a single printed word followed by what appears to be a variable-area sound track. It has been found that offset printing of sound tracks is practicable only up to about 200 cycles per inch. A minimum bandwidth of about 2000 cycles per second is necessary to represent normal speech components. Therefore, if it is assumed that the individual sound tracks of the Kallman patent are four inches long, it follows that each sound track contains less than half a second of minimum quality audible speech. This amount of sound track would be barely sufficient for a single word, much less an audio presentation of a group of words or a whole sentence.
Further problems of printed sound tracks relate to practical limitations in the optical transducer used to read and play the track. The optical unit cannot, of course, be unduly expensive. Generally, it is envisioned that the optical means would be manually scanned over the track thereby obviating the need for sophisticated optical scanning equipment. Manual scanning, however, gives rise to new problems that relate to the coordination and dexterity of the person handling the scanning means. First of all, the conventional printed sound track would be susceptible to frequency variations which are a function of manual scanning speed. This would result in words becoming blurred or unintelligible if the scanning speed during a line was varied significantly from the prescribed speed. A further problem of manual scan concerns physical registration of the scanning head with the sound track. Most systems would suffer severe degradation in the event that the user did not scan a relatively straight line that covered the desired track in its entirety. Also, provision must be made to minimize the possibility of the scanner overlapping (and therefore extraneously reading) printed text or adjacent tracks at the same time. Normally, this requires a relatively large empty or "dead" space between a line of sound track and other printed material, a clearly wasteful alternative. The combination of length-consuming sound tracks and the large dead space between tracks leaves little room for conventional printed material on a page.
It is an object of the present invention to provide a novel system for generating audible information from indicia printed on paper, the system substantially overcoming many of the disadvantages listed hereinabove.